Major roads could be turned into tunnels covered with pollution-absorbing material in an effort to cut emission fumes and improve air quality.
Highways Agency officials are studying a Dutch scheme in which cantilevered canopies are constructed over the most polluted sections of road to prevent local residents breathing in noxious car fumes.
Poor air quality is reported to kill as many as 40,000 people a year prematurely in the UK, and levels in many areas regularly breach European legal limits. The government has twice had its plans to tackle the issue ruled illegal by the courts.
The tunnel plans are outlined in an air improvement strategy plan to help reduce pollution. Officials say they are investing millions of pounds in new technology to improve air quality around roads in the next five years. The Department of Transport predicts traffic volumes are expected to increase by 55 per cent between 2010 and 2040.
“The best solution to accommodating the extra traffic on our roads, without negatively impacting on air quality, is cleaner low-emission vehicles. In the meantime we are investing £100m to test new ideas including less-polluting fuels and road barriers which can absorb harmful emissions,” said an agency spokesman.
“We have identified that a cantilever barrier or canopy, which is a tunnel-like structure designed to prevent vehicle emissions, might be a possible solution, though the air quality benefits of this are still to be fully understood. We are now working with the Dutch Roads Authority to measure air quality around an existing cantilever barrier on their network.”
Highways officials said they have also trialled two different types of barriers. The first, featuring wood panels 4 metres and 6 metres high, were fitted to the M62 near junction 18 in Manchester.
A second trial, which is ongoing, features a 3 metre high fence coated in a mineral polymer material capable of absorbing nitrogen dioxide. “The results from the monitoring of this trial will help us understand if this has been a success with the potential to implement it on the rest of our network,” said a Highways Agency spokesman.
A Highways England spokesman said on Wednesday they were also carrying out emission testing from a range of diesel vehicles using a new type of fuel believed to help improve emissions on both motorways and urban driving.
To help boost electric car use they will aim to ensure that 95 per cent of the roads network will have a vehicle charging point every 20 miles.